Articles, Blog

New strategy to enhance the efficiency of cereal straw for biofuel production

August 30, 2019


Commonly used for feeding animals, burning and baling, straw is known as one of the three Canton Treasures. What many don’t know is
that it can also be used as a raw material to produce biofuel. Increasing demand for
biofuel in recent years has prompted the use of cellulose from non-edible plant materials
like sugarcane leaves, corn stalks, and rice straw in
the production of bioethanol, a cleaner, renewable biofuel traditionally produced by fermentation of sucrose from sugarcane
or glucose from corn starch. However, since cellulose
is cross-linked with lignin in plant cell walls, it is very difficult to release glucose from it. To tackle this difficulty, a collaborative research
was started two years ago by plant biochemist Dr Clive Lo and his student, Dr Lydia Lam, from The University of Hong Kong. Together with Kyoto
University lignin specialist Dr Yuki Tobimatsu, the research team has recently revealed a new strategy to allow cellulose in rice straw to release fermentable
sugar more efficiently. This breakthrough was published in a notable plant science
journal – Plant Physiology. Lignin is a complex polymer which functions to provide
mechanical strength and structural integrity in plants. However, expensive and
complicated procedures are required to loosen the lignin barrier in order to utilise
cellulose more efficiently during the production of bioethanol. Rice and other cereals
below to the grass family. Lignin in their stems and leaves contain a special component called tricin. According to the research
team’s discovery, when flavone synthase II (FNSII), a key enzyme involved in tricin synthesis, is knocked out, not only
is tricin not produced, but the lignin content in rice straw was also reduced by approximately one-third. In addition, the glucose
yield is increased by 37% after cellulose degradation without any lignin treatment. The glucose so released can be used for bioethanol production. In other words, it is more efficient to produce ethanol from
this kind of rice straw. The lignin treatment costs can be reduced while the production of
biofuel can be enhanced. This is the first demonstration of the reduction of
cell wall lignin content in rice straw by the disruption
of tricin production. Importantly, there are no negative impacts on rice growth and productivity. As plants in the grass family all contain tricin-bound lignin, this strategy can be
applied to other cereals like corn, wheat, and barley
as well as grass species such as sorghum and switchgrass cultivated around the world exclusively for ethanol production so that they can be
utilized more efficiently as raw materials for biofuel. I’m very delighted and honoured to conduct a research project that could benefit society. Also, as a Hongkonger, I’m
always trained to work quickly and efficiently. During the eight-month research experience at Kyoto University, I was particularly impressed by the students there. They performed experiments with
extreme care and precisions. When I’m doing research today, I always ask myself to
do it better than perfect in addition to seeking
speed and efficiency.

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